A collision avoidance system and method creates 3D models of objects by collecting character data of the objects, and controls a camera of a vehicle to capture an image in front of the vehicle. The system determines whether an object is detected in front of the vehicle by comparing the image with each of the 3D models, analyzes a distance between the camera and the object according to the image, and determines whether the distance is less than a safety distance. The system controls the warning device to alarm when the distance is less than the safety distance, and automatically controls the brake system to reduce a speed of the vehicle if the vehicle is not decelerating.